The best free security software 2017

The best free security software

Reliable antivirus is essential for any internet-connected PC, but it isn’t always enough. Your security software should also protect you from malware – programs that don’t behave like viruses, but are nevertheless a nuisance and a threat to your security. All it takes is forgetting to uncheck a box when you download an otherwise legitimate program, and your PC is compromised.

Your main security software must provide real-time scans to help you avoid an infection in the first place, but on-demand scanners also have their place, identifying and removing any malicious software if your PC has started to behave strangely.

Your online accounts are a particularly juicy target for criminals too, so it’s also wise to use a password manager to create strong logins and store them in a secure vault.

We’ve ranked the best free security software in order of priority, starting with strong general purpose packages, through to preventative tools for specific threats. Combining several of these will enable you to create your own free security software suite, but bear in mind that you should only install one antivirus tool at a time.

1. Avast Free Antivirus

The best free security software, Avast safeguards your PC from threats the moment they appear

Avast Free Antivirus has millions of users, which helps it identify threats as soon as they appear. It scans your PC in real time, and if it comes across a piece of code that looks suspicious, it’s sent to Avast’s labs for testing. If it’s found to be malicious, Avast creates a ‘vaccine’ to eliminate it, which is then sent to every user worldwide.

Avast Free Antivirus can remove unwanted browser extensions and toolbars, which are easy to accidentally install if you often download free software, and there’s also a program updater to patch any recently discovered vulnerabilities in your installed software. It even includes a password manager to keep your logins secure.

Malwarebytes Anti-Malware was one of the first tools to successfully remove the infamous Locky ransomware that appeared last year

2. Malwarebytes Anti-Malware

Supplement your core security software with on-demand malware scans

Malwarebytes Anti-Malware runs in tandem with your main security software, providing specific protection from threats other than viruses.

The free edition of Malwarebytes Anti-Malware gives you reliable protection for malware and spyware, as well as rootkits, which give software access to crucial parts of your system without your permission.

The free edition of Malwarebytes Anti-Malware gives you a two-week taster of its premium features, including real-time scans, and protection from malicious sites, exploit attacks and ransomware (which it differentiates from other malware).

Once that trial period is up, you’re left with a no-frills on-demand scanner that’s ideal for removing unwanted software and identifying the cause of strange browser behaviour or taking back control of your browser if it’s been hijacked by adware.

Keepass shows the strength of your account passwords, and can generate stronger ones. They’re all stored in a securely encrypted central vault

3. Keepass

With so much of our data now stored online – including work, photos, emails, bank account details – strong passwords have never been more important. Unfortuantely, the sheer number of online accounts necessary for everyday life means it’s hard to think up and memorize a different strong password for every service.

Keepass does the hard work for you, and stores the resulting strong passwords in an encrypted vault protected by a master login or key file.

Keepass encrypts usernames, passwords and notes using the Advanced Encryption Standard (AES) and Twofish algorithms, and they remain encrypted while the program is running so they won’t be cached to disk. Unlike Avast Free Antivirus’s built-in password manager, Keepass is portable, so you can carry it on a USB stick and it won’t save anything to your Windows registry.

Best of all, because it’s open source, it’s in constant active development and any security vulnerabilities can be patched the moment they’re discovered.

If you have to deal with an infected PC, Emsisoft Emergency Kit can identify the virus and isolate it to prevent it doing further damage

4. Emsisoft Emergency Kit

If your antivirus software has failed and your PC’s security has been compromised, you need Emsisoft Emergency Kit .

Like Keepass, Emsisoft Emergency Kit can be saved to a USB stick and run on any PC without being installed (somewhat confusingly, it does have an ‘installer’, but this just extracts the necessary files and saves them to a location of your choice).

Not only does Emsisoft Emergency Kit check for viruses, trojans and worms, it also looks for malware on your PC, including adware, spyware and keyloggers. Bear in mind that these threats are constantly changing, so you’ll have to wait a minute for the security software to update its database of definitions before you can begin scanning.

Emsisoft Emergency Kit won’t conflict with any existing antivirus software on your PC, making it a great little tool to keep on hand. Even if you never need to use it yourself, it might be a lifesaver for a friend or family member who’s a little less cautious about their online security.

It’s all too easy to accidentally install toolbars and browser plugins when you download free software that’s supported by ads. As its name implies, Unchecky automatically unchecks boxes in software installers so you don’t get any surprises

5. Unchecky

Uncheck tick boxes to catch sneaky malware and toolbars before they install themselves

Unchecky won’t detect or remove malicious programs, but it can help you avoid installing them in the first place by automatically unchecking the boxes in software installers and alerting you if the app you’re installing is bundled with something else.

As security software, Unchecky isn’t perfect – it doesn’t pick up all unwanted programs, and some installers try to catch you out by taking an unchecked box as consent – but it’s nevertheless a useful tool in your PC security arsenal.

Combined with a common sense approach (only download software from a source you trust, select a ‘custom install’ option if it’s offered, and read each step of software installers carefully), it will help protect you from unwanted extras that pose a threat to you online.